Semiautomatic firing mechanisms for firearms use some of the energy of combustion gases from firing a bullet to eject the spent bullet casing, load a fresh cartridge into the firing chamber, and re-cock the firing mechanism so that the fresh cartridge may be subsequently fired, and the cycle repeated. To maximize the energy imparted to a bullet, and to enhance the accuracy of the fired bullet, it is often desirable to provide a “dwell” such that the spent bullet casing remains substantially in place immediately after the bullet is fired, before the reloading and re-cocking sequence is substantially begun.